Modular Air-Conditioning System and Method for the Operation Thereof

ABSTRACT

A modular climate control system, particularly for generating cold and/or heat, includes one or more modules, a working medium or coolant being condensed, liquefied, relieved and re-evaporated in a circuit in the modules, and the heat and/or cold generated in the process is delivered to corresponding secondary circuits via heat exchangers. High flexibility in the use of the system, and tremendous simplification in the set-up and modification are achieved because a common collector including collector tubes is provided for several modules. The modules are detachably connected to the collector, and the collector connects the modules to the respective secondary circuits.

It has been known for some time (U.S. Pat. No. 6,185,946 B1), in air-conditioning systems, to connect a plurality of identical subsystems in parallel and to cause them to operate in parallel, in order to increase the overall efficiency of the system, subsystems being cut in or cut out during operation, as required. No further statements are made in detail on the type of parallel connection.

Furthermore, an apparatus for the thermal control of a liquid is known (DE-93 19 004U), in which a plurality of cooling units are present which can be built one onto the other and which in each case contain a refrigerating machine, the forward and return path for the liquid to be thermally controlled being assembled in pieces by means of the individual cooling units.

Accordingly, it is impossible to extend the system or to exchange a cooling unit without stopping the operation of the entire system. The same also applies to the modular treatment apparatus for fluids which is disclosed in DE-A1-36 13 535.

EP-A2-1 072 849 discloses a refrigerating system with an indirect cooling system, in which a plurality of independent primary modules form a primary circuit which is connected to corresponding secondary circuits. The primary modules are arranged in a frame receiving the primary modules and are connected to the secondary circuit or to the secondary circuits via a connection system co-ordinated with the primary modules. The connection system comprises, on the one hand, the power supply and, on the other hand, easily handled connection points to the respective forward and return run of the secondary circuit. What is achieved thereby is that the refrigerating devices are concentrated in the (encased) primary modules, and the remaining connection and maintenance work can be carried out by personnel not trained in refrigeration technology. More detailed particulars on the structural configuration of the connection system and the secondary circuits are not given.

Finally, the applicant's WO-A1-2004/020918 discloses an air-conditioning system in which, by a modular type of construction (refrigeration sets), frequency control of the refrigerant compressors, parallel connection of the refrigerant compressor circuits, two-stage evaporation with internal liquid supercooling and suction vapor superheating, two-stage or multistage supercooling, displacement and storage of the refrigeration energy from times of low demand to times of high demand, integrated waste heat utilization, and cascade and emergency operation at module, plant or system level, special advantages with regard to operating reliability, operating costs, maintenance costs, simple plant technology, simple capacity matching to required refrigerating capacity (extension stages) and simple and flexible matching to possible waste heat utilizations are achieved. Here, too, more detailed particulars of the structural configuration of the overall system are not given.

The object of the invention is to provide an air-conditioning system of modular set-up, which can be set up in normal spaces simply and without difficulty, can easily be matched to different air-conditioning requirements and, in particular, allows an exchange of modules or an addition of further modules during continuous operation, and also to specify a method for the operation thereof.

The object is achieved by means of the whole of the features of claims 1, 19 and 20.

It is essential to the invention that, for a plurality of modules, a common collector is provided which is constructed from collecting tubes and to which the modules are releasably connected, and which connects the modules to the respective common secondary circuit. The collector forms an independent unit which makes available one or more complete secondary circuits, to which modules can be connected or uncoupled, as required, without the secondary circuits being interrupted or impaired.

One refinement of the invention is distinguished in that the collector with its collecting tubes extends horizontally in a longitudinal direction, in that a series of reception spaces for the reception of modules are provided on the collector in the longitudinal direction, in that the collecting tubes are formed continuously over a plurality of reception spaces, and in that, to connect the modules to the collecting tubes, in each case corresponding outlets are provided on the collecting tubes in the region of a reception space. This affords in a particularly simple way the possibility of connecting a plurality of collectors in series when even more modules are to be incorporated into the system. For this purpose, in particular, the collectors may be designed so as to be capable of being lined up with one another.

According to another refinement, the collector comprises a rack which extends in the longitudinal direction and stands on the floor and in which the reception spaces for receiving the modules are left free, the collecting tubes being fastened to the rack. In particular, the collecting tubes are mounted in the rack above the reception spaces for receiving the modules, the collecting tubes being mounted in the rack in a plurality of planes lying one above the other. This makes it possible to install or exchange the modules in a simple way, without fastenings on the ceiling or elsewhere in the associated space being necessary.

Preferably, the collector has per secondary circuit in each case two collecting tubes for the forward run and return run of the associated secondary medium, the collecting tubes for the forward run and the collecting tubes for the return run being mounted on different planes.

Another refinement of the invention is distinguished in that each of the modules is assigned at least one control loop containing regulating means, in particular regulating valves, in that the control loop is arranged hydraulically between the associated module and the collecting tubes, and in that the control loop is fastened to the rack. It is thereby possible to have a modularization and preassembly of the regulating devices, which greatly simplifies the set-up and adaptation of the system.

Preferably, each module stands independently in its reception space on the floor, and the associated control loops are connected, on one side, directly to the outlets of the collecting tubes and, on the other side, via hose connections to the module. Electrical and vibratory decoupling of the modules and collector thereby becomes possible. Furthermore, deviations in the interface geometry can be absorbed.

In particular, at least one of the control loops may comprise a pump which is arranged in one of the secondary circuits of the associated module. It is also conceivable, however, to provide a central pump per secondary circuit and to dispense with local pumps in the control loops.

Preferably, each module is accommodated in a specific rack and stands with adjustable feet, arranged on the rack, on the floor, so that the installation and demounting of the module are very simple.

Another refinement of the invention is characterized in that each of the collecting tubes of the collector is dimensioned such that the overall cross section of the outlets of the collecting tube which lead to the modules is smaller than the cross section of the collecting tube itself.

Furthermore, advantageously, in each case a switch cabinet is provided for supplying the modules or the associated control loops with electrical energy and control signals, the switch cabinets preferably being fastened in each case to the associated module. If the switch cabinet is fastened to the module, it can advantageously be delivered, together with the module, as a prefabricated and wired-up unit. If a module fails, the switch cabinet can be demounted from the module before the removal of the module and can be suspended temporarily on the collector.

In each case at least one control cable and one junction cable are provided for electrical connection between the modules and the associated switch cabinets, and at least the connection by means of the control cable is designed to be pluggable, in order to simplify the installation and demounting of a module. All the cables to the system circuits (pumps, valves, frequency converters, etc.) and the cable from the main distributor (master fusebox) to the switch cabinet are preferably permanently wired up. In the same way, for reasons of simplicity, the junction cable from the switch cabinet to the compressor is not designed to be pluggable, although it could basically be connected by means of plugs.

Another refinement is characterized in that each of the modules comprises, in its circuit, at least one compressor, an, in particular controllable, injection valve, an evaporator and a condenser, and in that the external dimensions of the modules are selected such that they can be transported through any door having a free passage of 80 cm. In addition, one or more modules may have an internal heat exchanger IWT and, if appropriate, a stabilizer. One or more modules may also additionally have a deheater and/or a supercooler.

One method according to the invention for operating the modular air-conditioning system is characterized in that, after the failure of one of the modules during continuous operation, the hydraulic connections of the failed module to the collector are disconnected, the module is uncoupled from the collector and replaced by a new module of identical type, the new module is connected to the collector, and the hydraulic connections to the collector are reconnected.

The other method according to the invention for operating the modular air-conditioning system is characterized in that, to vary the characteristic or capacity of the system during continuous operation, the hydraulic connections of a selected module to the collector are disconnected, the module is uncoupled from the collector and replaced by a new module of another type or capacity, the new module is connected to the collector, and the hydraulic connections to the collector are reconnected, or an additional module is connected to the collector.

The invention will be explained in more detail below by means of exemplary embodiments, in conjunction with the drawing, in which:

FIG. 1 shows the greatly simplified block circuit diagram of a refrigerating module known per se;

FIG. 1 a shows a refrigerating module comparable to FIG. 1 with an additional stabilizer;

FIG. 2 shows the connection of a simplified refrigerating module similar to FIG. 1 to a collector according to one exemplary embodiment of the invention;

FIG. 3 shows the connection of a multiplicity of refrigerating modules to a collector according to another exemplary embodiment of the invention;

FIG. 4 shows a front view of a collector capable of being lined up with others and having two pushed-in modules, according to a further exemplary embodiment of the invention, the control loops RK assigned to each module being indicated merely as blocks;

FIG. 5 shows various types of control loops RK with and without (local) pumps, such as are used in FIG. 4; and

FIG. 6 shows the arrangement from FIG. 4, as seen in the longitudinal direction.

The solution proposed here is based centrally on modular technology. The modularity in this case extends through the entire new development and, if possible, embraces all the regions. In the case of the cold generation modules (as already illustrated earlier in WO-A1-2004/020918), the modularity extends over the system application region: The identically constructed modules will be used as heat pumps, air-conditioning systems, cooling systems, freezer systems, etc. (different conditions of use for different processes are possible).

However, modularity even extends over the area of type of construction: The same components are employed as often as possible. Nevertheless, user requirements are to be capable of being dealt with individually. Thus, with an identical type of construction, the refrigerant can be changed, depending on the process and user's wish. For example, the same modules may be operated with R134a or R404a or, correspondingly, with other suitable refrigerants. This, of course, also results in each case in other capacities, etc. As desired, different compressor makes can be installed in the same modules, but also different compressor types can be employed, such as, for example, reciprocating piston compressors, screw-type compressors, scroll compressors, etc.

FIG. 1 reproduces in a greatly simplified form an exemplary module M of a refrigerating plant, such as is described in the earlier application WO-A1-2004/020918 (see FIG. 4 therein). The module M of this example comprises a circuit 11 for a refrigerant, with a compressor 12, with a (regulated) injection valve 13 for depressurizing the refrigerant, with an evaporator and with a condenser 17. In addition, an internal heat exchanger (IWT) 14 is provided, which can operate, in particular, as a second evaporation stage, in order to stabilize operation when work is being carried out over a long thermal length of the heat exchanger.

Furthermore, a deheater 16 and a supercooler 18 may optionally be employed in the circuit 11. If the deheater 16 and supercooler 18 are dispensed with, the circuit 11 is closed by means of the connecting lines 19 and 20 depicted by dashes in FIG. 1. In addition, according to FIG. 1 a, a stabilizer 15′ may be installed between the injection valve 13 and the evaporator 15, in order to stabilize the refrigerating circuit even further and to keep undesirable control fluctuations low.

The secondary sides of the heat exchangers 15, . . . , 18 are led out by line from the module M and in the simplest instance are connected via shut-off valves V1, . . . , V8 to secondary circuits, not shown in FIG. 1, in which the exchanged heat or cold is transferred and utilized by means of appropriate secondary media. The evaporator 15 in this case includes, as a secondary circuit, an evaporator circuit in which, for example, brine is routed to a cooling shelf or other cooling locations. The condenser 17 includes correspondingly, as a secondary circuit, a condenser circuit which discharges the heat occurring during condensation into the surroundings or otherwise utilizes it. These two secondary circuits must in any event be connected. If, in addition, a supercooler 18 and deheater 16 are also used in the module M, there are also a supercooler circuit and a deheater circuit as associated secondary circuits.

According to the invention, then, for a plurality of modules a common collector is provided which is constructed from collecting tubes and to which the modules are connected releasably, and which connects the modules to the respective secondary circuit. This “collection” is illustrated diagrammatically in FIG. 2 for a single module M without a deheater and supercooler: the collector K comprises a plurality of collecting tubes 21, . . . , 24 which run parallel in a longitudinal direction and which are accommodated in a common rack 28 (see also FIGS. 4 and 6) extending in the longitudinal direction. Each secondary circuit includes a pair of collecting tubes 21, 22 and 23, 24 which serve in each case for the forward run and return run in the corresponding secondary circuit. In the example of FIG. 2, the collecting tube 21 is responsible for the forward run and the collecting tube 22 for the return run in the condenser circuit. Correspondingly, the collecting tube 23 is responsible for the forward run and the collecting tube 24 for the return run in the evaporator circuit. The collecting tubes 21, . . . , 24 lead to the system parts, not illustrated in the figures, which in each case complete the secondary circuits. If a deheater 16 and supercooler 18 are additionally provided, there are in the collector K collecting tubes for the associated secondary circuits (in FIG. 6, 41 designates the two collecting tubes for the return run in the supercooler and deheater circuit and 42 designates the corresponding collecting tubes for the forward run in the two secondary circuits).

The collector K extends in the longitudinal direction over a plurality of reception spaces (AR, depicted by dashes in FIG. 3) which are lined up one behind the other in the longitudinal direction and are designed in each case for receiving one of the standardized modules M. A module M can be pushed into each of the reception spaces AR, as required, and can be connected to the collecting tubes 21, . . . , 24, in order to increase the refrigerating capacity of the overall system or (for example, in the form of a heat pump) to provide other thermal or air-conditioning functions. In the event of an operating failure or a lack of demand, a module M standing in a reception space can likewise be uncoupled from the collecting tubes 21, . . . , 24 and exchanged or demounted without replacement. All these variations in the system can be carried out, without the operation of the overall system comprising a plurality of modules M having to be interrupted. Only the mass flow in the collecting tubes changes according to the proportion of the respective module in the overall system.

FIG. 3 reproduces a simplified block circuit diagram of a modular air-conditioning system 10 according to an exemplary embodiment of the invention. The modularity in the construction of the system is based essentially on the following module components which can be individually matched singly or multiply to user or process requirements:

-   -   Rack (34 in FIG. 4)     -   Compressor 12     -   Heat exchanger 14, . . . , 18 (heat exchanger block)     -   Injection valve 13     -   Refrigerant     -   Switch cabinet SS1, . . . , SSn

The concept, the pipework, the insulation, the safety devices, etc. of the module M in this case always remain (as far as possible) identical.

The individual modules M1, . . . , Mn are assembled (collected) into systems (system 10), and individual assembled systems can, in turn, be connected to one another, further, into large systems. Depending on process requirements, one or more modules which are collected into a system are sufficient. The individual modules may be (but do not have to be) identical in terms of capacity or type of construction. The system size is dependent on the secondary medium (water, propylene, ethylene, etc.), on the maximum cold or heat capacity (condensation capacity), on the desired or required temperature difference of the secondary medium or on the mass flow conveyed and the associated flow velocity. In this case, preferably, a line cross section with a diameter of DN 150 mm is used as a standard for the collecting tubes 21, . . . , 24. A corresponding number of modules M with low capacity or a smaller number of modules M with high capacity can then be connected to a collector K.

The individual modules M are designed in terms of the external dimensions so that they pass through any door having a free passage of 80 cm. This ensures that a system 10 of the type described can be assembled in a “normal” space without special structural modifications. Correspondingly, the collector should also be capable of being set up in any “normal” space. A floor support of the collector K is therefore used (see FIGS. 4 and 6) which additionally has the advantage that no ceiling installations are necessary and conflicts with other air-conditioning or electrical devices mounted on the ceiling are avoided. The maximum height of the collector K is preferably limited so that it is possible for it to be set up in a space having a space height of 2.50 meters.

In the exemplary embodiment of FIG. 3, a plurality of modules M1, . . . , Mn accommodated in corresponding reception spaces AR of the collector K are connected via associated control loops RK to the collector K with its collecting tubes 21, . . . , 24. Further collecting tubes in the collector K for any deheater or supercooler circuits are not shown here for the sake of simplicity, but are illustrated in FIG. 6 (collecting tubes 41, 42). In the control loops RK, valves are indicated which take over shut-off and/or regulating functions. The actual internal set-up of such control loops RK is shown by way of example in four different variants in FIG. 5.

The electrical supply and control of the individual modules M1, . . . , Mn take place via associated switch cabinets SS1, . . . , SSn which are connected via separate feed lines 25 to a main distribution point (not illustrated) and which are connected via (preferably pluggable) control cables 26 and (preferably permanently wired-up) junction cables 27 (for the power supply of the compressor 12) to the respective module. Electrical connections 26 a for any pumps, valves, etc. connect the respective control loops RK to the respective module switch cabinet. The individual modules M1, . . . , Mn can be connected to their switch cabinets SS1, . . . , SSn via a common databus 39. The switching commands ON and OFF, the collective alarm, etc. can thus be transmitted to what is known as a “Master” or come from there.

The preferred set-up of the collector K is illustrated in FIGS. 4 to 6 for the air-conditioning system 30. The collector K with its rack 28 is supported from the floor on brackets. It (like the modules M, too) has feet 33 for leveling in the event of unevennesses of the floor. The collecting tubes 21, . . . , 24 (or 41, 42 in FIG. 6) which are fastened to the rack 28 are formed continuously over a plurality of reception spaces AR. For connecting the modules M, M1, M2 to the collecting tubes 21, . . . , 24; 41, 42, in each case corresponding outlets 32 are provided on the collecting tubes 21, . . . , 24; 41, 42 in the region of a reception space AR. The collecting tubes 21, . . . , 24; 41, 42 are mounted in the rack 28, above the reception spaces AR for receiving the modules M, M1, M2, in a plurality of planes lying one above the other. The collector K has in each case per secondary circuit two collecting tubes 21, 22 and 23, 24 and 41 and 42 for the forward run and return run of the associated secondary medium. The collecting tubes 21, 23, 42 for the forward run and the collecting tubes 22, 24, 41 for the return run are in this case mounted on different planes by corresponding 31 and 29. The collecting tubes 21, . . . , 24 of the collector K are dimensioned (DN 150 mm) so that the overall cross section of the outgoing tubes (outlets 32) to the modules M, M1, M2 is smaller than the overall cross section of the collector K (uniform distribution to all outgoing tubes).

The collector K can be connected at both ends by means of corresponding flanges, screw couplings, etc. It is thereby also possible for a plurality of collectors K to be lined up with one another. The material of the collector K (of the collecting tubes) may be different, depending on the conditions of use, such as, for example:

-   -   high-grade steel     -   plastic     -   copper     -   steel, black     -   steel, galvanized

In the example of FIGS. 4 to 6, the modules M, M1, M2 have in each case four secondary circuits, the first two having to be connected in any event, but the last two sometimes not having to be connected, depending on system requirements:

-   -   evaporator circuit (cooling) must be connected     -   condenser circuit (heat) must be connected     -   supercooler circuit (optional, remaining free)     -   deheater circuit (optional, remaining free)

Depending on the temperature range and processes used, no lines, individual lines or all lines are insulated according to respective requirements. The collector K can be constructed according to “present-day demands” and, if it is to be extended, can be extended later in a corresponding way (addition of a further collector at the existing collector end).

The control and regulation of the individual secondary circuits are set up in a modular manner with individual control loops RK1 (RK in FIG. 5) and can be prefabricated according to the appropriate interface. A distinction may in this case be made as to whether a pump 37, 38 is to be used per module and secondary circuit, or in each case a central pump, and/or, depending on the process, for example, the supercooler is to be equipped with a central pump for all modules and the other secondary circuits are to be equipped in each case with a specific pump per module. Correspondingly (depending on the process), two-way, three-way, shut-off and/or section-regulating valves are installed (FIG. 5). Deheater and supercooler circuits which are provided in the modules M, M1, M2 may also be connected at a later time.

The collector K always has defined interfaces and is assembled, as required, from different modules:

-   -   It is designed for two or more modules M (up to the maximum         possible number). The interface is defined via a hand valve         (ball valve, etc.) and a following releasable connection         (flange, etc.).     -   The collected secondary circuits are a minimum of two circuits         (evaporator and condenser circuits), 4 collecting tubes DN 150         mm.     -   Depending on the process, different control loops RK suitable         for the respective interfaces are used.     -   According to FIG. 6, hose connections 36 to the modules M are         provided, which compensate dimensional tolerances between the         module M and collector K, separate different metals galvanically         from one another (electrical separation, potential compensation)         and prevent the transmission of vibrations and pulsations         between the modules M and the collector K.

The switch cabinets (SS in FIG. 6) are likewise constructed in a modular manner. The control cables (26 in FIG. 3) between the module M and switch cabinet SS are routed via plugs, and the compressor junction cable is permanently wired up. The individual switch cabinets SS have identical control and regulating components (depending on process requirements). A master gives the respective (ON/OFF) commands during automatic operation via the databus 39. One, two or all modules M may be equipped (even subsequently) with a frequency converter, as is shown in FIG. 4 of WO-A1-2004/020918. When a module M is changed, the switch cabinet SS (initially fastened to the module) remains on site, and only the modules are changed (control part pluggable, power part routed to terminals). The protection of the modules M is implemented “at the factory” by the subdistributor.

Overall, the main components of the proposed collection are:

-   -   air-conditioning module (refrigerating modules, heat pump         modules, etc.)     -   switch cabinet (per module)     -   carrying stand (rack) collector     -   collecting tubes with defined interfaces     -   regulating and control components (valves, pumps, etc.)     -   hose connections

If the modules are to be employed in a different way during their service life (process changes, change of location, extensions, etc.), the modules and the collection can be adapted in a simple way and used further, a space with standard dimensions being sufficient as an installation location for the system 10 or 30. Smaller modules (in terms of capacity) can easily be exchanged later for modules with a higher capacity.

LIST OF REFERENCE SYMBOLS

-   10,30 Air-conditioning system (modular) -   11 Circuit -   12 Compressor -   13 Injection valve -   14 Internal heat exchanger (IWT) -   15 Evaporator -   15′ Stabilizer -   16 Deheater -   17 Condenser -   18 Supercooler -   19,20 Connecting line -   21,22 Collecting tube (condenser circuit) -   23,24 Collecting tube (evaporator circuit) -   25 Feed line -   26 Control cable (pluggable) -   26 a Electrical connection -   27 Junction cable (to the compressor, permanently wired up) -   28 Rack (collector) -   29,31 Carrier rail -   32 Outlet -   33 Foot (rack) 34 Rack (module) -   35 Foot (module) -   36 Hose connection -   37,38 Pump (module) -   39 Databus -   40 Junction line (permanently wired up) -   41 Collecting tube (return run) -   42 Collecting tube (forward run) -   AR Reception space -   K Collector -   M,M′,M1,M2,Mn Module -   RK,RK1,RK2 Control loop -   SS,SS1,SS2,SSn Switch cabinet -   V1, . . . , V8 Valve 

1-20. (canceled)
 21. A modular air-conditioning system for cold and/or heat generation, comprising one or more modules, wherein, in each module, a working medium or refrigerant is compressed, condensed, depressurized and evaporated again in a circuit, and the heat or cold generated is discharged to corresponding secondary circuits via heat exchangers, wherein a common collector is provided for the modules which is constructed from a plurality of collecting tubes and to which the modules are releasably connected, and which connects the modules to the corresponding secondary circuits.
 22. The modular air-conditioning system as claimed in claim 21, wherein the collector constructed from the collecting tubes extends horizontally in a longitudinal direction, wherein a series of reception spaces for the reception of modules are provided on the collector in the longitudinal direction, wherein the collecting tubes are formed continuously over a plurality of reception spaces, and wherein, to connect the modules to the collecting tubes, corresponding outlets are provided on the collecting tubes in the region of a reception space.
 23. The modular air-conditioning system as claimed in claim 22, wherein the collector comprises a rack which extends in the longitudinal direction and stands on the floor and in which the reception spaces for receiving the modules are left free, and wherein the collecting tubes are fastened to the rack.
 24. The modular air-conditioning system as claimed in claim 23, wherein the collecting tubes are mounted in the rack above the reception spaces for receiving the modules.
 25. The modular air-conditioning system as claimed in claim 24, wherein the collecting tubes are mounted in the rack in a plurality of planes lying one above the other.
 26. The modular air-conditioning system as claimed in claim 25, wherein the collector has, per secondary circuit, two collecting tubes for a forward run and a return run of a secondary medium in the corresponding secondary circuits, and wherein the collecting tubes for the forward run and the collecting tubes for the return run are mounted on different planes.
 27. The modular air-conditioning system as claimed in claim 23, wherein each of the modules is assigned at least one control loop containing regulating valves, wherein the control loop is arranged hydraulically between the associated module and the collecting tubes, and wherein the control loop is fastened to the rack.
 28. The modular air-conditioning system as claimed in claim 27, wherein each module stands independently in its reception space on the floor, and wherein the associated control loops are connected on one side directly to the outlets of the collecting tubes and on the other side via hose connections to the module.
 29. The modular air-conditioning system as claimed in claim 27, wherein at least one of the control loops comprises a pump which is arranged in one of the secondary circuits of the associated module.
 30. The modular air-conditioning system as claimed in claim 28, wherein each module is accommodated in a specific rack and stands with adjustable feet on the floor.
 31. The modular air-conditioning system as claimed in claim 22, wherein each of the collecting tubes of the collector is dimensioned such that the overall cross section of the outlets of the collecting tubes which lead to the modules is smaller than the cross section of the collecting tube itself.
 32. The modular air-conditioning system as claimed in claim 21, wherein respective switch cabinets are provided for supplying the modules or the associated control loops with electrical energy and control signals.
 33. The modular air-conditioning system as claimed in claim 32, wherein the switch cabinets are fastened in each case to the associated module.
 34. The modular air-conditioning system as claimed in claim 32, wherein at least one control cable and one junction cable are provided for each electrical connection between the modules and the associated switch cabinets, and wherein at least the connection by means of the control cable is pluggable.
 35. The modular air-conditioning system as claimed in claim 21, wherein each of the modules comprises at least one compressor, a controllable injection valve, an evaporator and a condenser, and wherein the external dimensions of the modules are selected such that they can be transported through any door having a free passage of 80 cm.
 36. The modular air-conditioning system as claimed in claim 35, wherein at least one of the modules additionally has an internal heat exchanger and a stabilizer.
 37. The modular air-conditioning system as claimed in claim 35, wherein at least one of the modules additionally has a deheater and/or a supercooler.
 38. The modular air-conditioning system as claimed in claim 21, wherein the collectors are capable of being lined up with one another.
 39. A method for operating a modular air-conditioning system as claimed in claim 21, wherein, after failure of one of the modules during continuous operation, hydraulic connections of the failed module to the collector are disconnected, the failed module is uncoupled from the collector and replaced by a new module of identical type, the new module is connected to the collector, and hydraulic connections to the collector are reconnected.
 40. A method for operating a modular air-conditioning system as claimed in claim 21, wherein, to vary the characteristic or capacity of the system during continuous operation, the hydraulic connections of a selected module to the collector are disconnected, the selected module is uncoupled from the collector and replaced by a new module of another type or capacity, the new module is connected to the collector, and the hydraulic connections to the collector are reconnected, or an additional module is connected to the collector. 